Method of oxidizing steel or iron sheets.



A. 1. MASKREY. METHOD 0E oxmlzTNG STEEL 0R mow SHEETS.

I APPLICATION FILED OCT. I4. 1913. 19141;?190 PatentedJune 1, 1910.

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A. I. IVIASKREY. METHOD 0F OXIDIZING STEEL OP. IRON SHEETS.

APPLICATION FILED OCT. 141 1913. 19141,719, PntentedJvune 1, 1915.

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@MaI/ay ARTHUR J'. MASKBEY,.,OF CANTON, OHIO, ASSIGNOR OFONE-HALF TO JOHN E.

i GARNAHAN, OF CANTON, OHIO.

Speciicationvof -Letters Patent.

Patented J une 1, 1915.

Application med. October 14, 1913. Serial No. 795,095'.

To all whom t may concern:

Be it known that I, ARTHUR J. MASKREY, a citizen of theJ United States, residing at Canton, in the county of Stark and State of Ohio, have invented a certain new. and useful Method of Oxidizing vSteel or Iron Sheets, of which the following is a specification.

The invention relates tothe oxidization of the surfaces of annealed steel or iron. sheets for the purpose of giving them a `uniform bluish, color. AOrdinary processes of annealing such sheets frequently produce a varying colorI of oxidation thereon merging from a blackish to a dark blue color adjacent to the edges, into a distinctly lighter blue or silvery color in the middle portions of the sheet, which different colors are sometimes emphasized by the subsequent processes in finishing the sheets.

'It is believed that the varying color of oxidation from the edges to the middle portions of the sheets is caused largely, if not entirely, by the presence of gases of combustion from the heating furnace which find their way into an ordinary annealing box ,through the sand luted joints thereof and either form an oxid or a sulfid, depending upon the fuel used, upon the surfaces of the sheets as far inward from the edges4 thereof as the gases may permeate. And when it has been sought'to oxidize separate sheets by a direct or an indirect heat, it has been found that wherever the sheet has been previously handled, the marks of handling will be developed on the surfaces of the v sheets along with the oxidation, but of an entirely different and distinct color. This development is caused no doubt by the perspiration from the human hand, and the same diiiiculty results to a less extent, even though the sheets are handled with gloves.

The object ofthe present invention is to carry out the 'annealing process in such a manner as will permit such an oxidation as will give a uniform blue color to the surfaces of the sheets throughout the whole extentl thereof, when they are separated after being annealed; and thls object is attained by inclosing a gpack of sheets in a retort impervious to the ases of combustion or other heating means,l uring the annealing process,

and then removing the ack from the retort and separating the s eets and exposing them singly while at a red heat to the atmosphere, whereby the surfaces are oxidized to a unlform color. The annealing process forming'part of the improved method, may be performed in an annealing furnace having a retort therein as illustrated in the accompanying drawings, forming part hereof, in which- Figure 1 is a longitudinal section of the improved annealing furnace; Fig. 2, a plan section thereof on line 2 2, Fig. 1; Fig. 3, a front elevation of the same; and Fig. 4, a transverse section vthereof on line 3-3,

imilar numerals refer to similar] parts throughout the drawings.

The retort 1 may be composed of cast metal or other suitablyA impervious material and should be .closed on all sides excepting only at its mouth which is preferably' located at one end and is closed by the doors 2. Suitable runways 3 are laid in the bottom of the retort and extend Aforward through the mouth thereof, upon which the carrying plate 4 may be moved into and out of the furnace on the balls 5, whichrun in the grooves 6 of the runways and the grooves 7 provided on the under side of the carrying plate. The furnace 8 is built around the retort, excepting only the open end thereof, and may be of any suitable construction to properly heat the retort so that its contents'may be brought to an annealing temperature of approximately 14000 to 1600o F.

For carrying out the improved process, the sheets are assembled in a pack upon the carrying plate and then run into the retort, as shown in the several figures; after which the doors are closed, or other suitable means are employed for closing the mouth of the retort to retain the heat and exclude an excess of atmospheric air during the annealing process.

The retort is then heated by the furnace or other suitable means, until the sheets in the *pack a/re heated to a uniform temperature for the purpose of annealing, after which the mouth of the retort is opened and the pack of sheets withdrawn therefrom on the carrying plate, and the sheets of the pack are then separated and exposed t'o the atmosphere while at a red heat, for oxidlzingthe surfaces. 4

By heating the sheets in a pack in aretort impervious to the gases of combustion 1n lll@ the aniiealing process, it is evident that the` edge portions of4 the sheets will not be disthem/"a uniform color throughout the Whole extent. And again, it has been found that when sheets are heated in apack, as herein described, during a considerable period of time,they do not develop upon their surfaces such marks as may be present from handling in previous operations, so that the sheets Wheniinally oxidized, do not show the same; while a single sheet heated to a red heat during a comparatively short space of time, does develop such marks in such a manner as to practically destroy the uniormity of the colorthereof when oxidized.

I claim:

1. The process of oxidizing steel or iron sheets consisting in placing a pack of sheets in a retort impervious to the gases of combustion, then heating the sheets in the retort to an annealing temperature, then removing the pack of sheets from the retort and then separately exposing the sheets ARTHUR J. MASKREY Witnesses:

ELFRmDE SCHMIDT, CHAs. M. BALL. 

